On 08/01/2013 03:42 PM, Gleb Natapov wrote: > On Thu, Aug 01, 2013 at 03:31:01PM +0800, Xiao Guangrong wrote: >> On 08/01/2013 03:18 PM, Xiao Guangrong wrote: >> +#endif >>>>> >>>>> Hmm, why not use shadow_x_mask, shadow_user_mask instead? PT_WRITABLE_MASK >>>>> is also suitable for ept, i guess we can remove the "#if/#else/#endif" >>>>> after >>>>> that. >>>>> >>>> shadow_x_mask and shadow_user_mask do not depend on guest paging mode, >>>> so cannot be used here. Since we have to use ifdefs anyway relying on >>>> VMX_EPT_WRITABLE_MASK == PT_WRITABLE_MASK is not necessary. Makes code >>>> easier to read. >>> >>> Oh, yes, you are right. >>> >>> Reviewed-by: Xiao Guangrong <[email protected]> >> >> BTW, i notice the code in mmu.c uses PT64_NX_MASK to check the permission, >> i.e: >> >> static bool need_remote_flush(u64 old, u64 new) >> { >> if (!is_shadow_present_pte(old)) >> return false; >> if (!is_shadow_present_pte(new)) >> return true; >> if ((old ^ new) & PT64_BASE_ADDR_MASK) >> return true; >> old ^= PT64_NX_MASK; >> new ^= PT64_NX_MASK; >> return (old & ~new & PT64_PERM_MASK) != 0; >> } >> >> It checks shadow page table and the mask is wrong one nest ept spte. > So shadow_x_mask need to be used here, correct?
Yes. The code checks shadow page table which does not depend on guest mode. :) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
